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Topic Review (Newest First)

08-04-2010 06:16 PM

hotrodhenson

Is this a Mark IV bracket?

I bought a hotrod without calipers and I need to know what year model lincoln bracket this is to buy calipers. It has 11.5" rotors.

05-13-2010 10:59 PM

ph2ocraft

Along these lines, is there any adjustment for the parking brake on the 76 Lincoln set up?
I have good pedal feel but the truck still rolls. I was guessing I may just have too much travel at the lever attaching to the caliper and was wondering, other than cable adjustment is there away to change or adjust the pressure to the brake pads off the parking brake lever??

03-28-2009 06:47 PM

powerrodsmike

75 -76 lincoln MK IV came with single piston rear calipers, 2.6" diameter. All of the disc brake rear Lincolns, Mercurys used single piston calipers with an emergency brake , Those 2 piston calipers in the pics are not off the rear of any Ford product that I ever saw. They look an awful lot like f250 front calipers to me. The Lincoln disc rear has a different axle bearing with an external seal and different hub offset than a drum brake axle, maybe a full size station wagon drum and backing plate would fit. You will wind up playing around with the axle retainer plate too, because the external seal won't clear the hole in the center. But then you'd have fun trying to get the drum in the right place .. IMO, you would be better off finding a wilwood set for the rear, and going to a smaller master cylinder..

The stock Lincoln mc was 1 1/8" and used a hydroboost. Just FYI, the front calipers that are supposed to be used with those rears are 3.1" piston diameter. Those front wilwoods are not anywhere near the size in piston area that the rear pistons are, that's where the bias problems will come from.

If the front calipers have 2 (or 4) 1.75" pistons, the effective piston area is 4.9 square in. The 2.6" rear calipers have an area of 5.31 sq in..so the front piston area is about 90% of the rear...it should be the other way around, with the rear piston area being 60 to 70% of the fronts... The lincoln disc diameter is larger than the fronts as well..that will only compound your problem...

Later, mikey

03-28-2009 06:26 PM

whynot

Ok ! The rear does have 2 large pistons in the factory caliper like 2" dia. each. So its a lot larger area. You can see the cylinders in the pictures of the old calipers.
And yes its a lot larger area then whats in drum brakes.
So with that said. How about me changing my rear end over to a drum brake setup. This means like totally stripping my rear down and replacing everything new. Like back plate, shoes,springs,wheel cylinder,drums and etc. This maybe great and work. But I am wondering about 2 parts,ill throw the rest out. I like to use the rear housing and the axles if I can. The reason being the housing is narrowed and the axles are shorten Moser racing axles.
So it brings me to wonder if both disc and drum axles are factory built the same ? Anyone know or how can i find out if they are the same ?

03-28-2009 10:21 AM

powerrodsmike

Here are pics of the 2 piston caliper that whynot sent to me....I post them here for him.

03-28-2009 10:09 AM

powerrodsmike

whynot sent me some pics of his setup, I'll post them here. There was a couple of pictures of the mentioned 2 piston calipers, but as they were not mounted on the car, I left it out. ( I don't recognize them, but they look like fronts to me.)

One of the problems lies in the fact that those wilwood calipers in the front need alot of pressure to work, and are designed to use a small master cylinder, while the rear calipers have a great deal more piston area, and require a bunch of volume and pressure to work..even when adjusted...so they need a larger master cylinder...That's why folks have a problem with the front /rear brake bias when they run the lincoln brakes on the rear... The last car I straightened out with the Lincoln Versaille rear brakes and small piston front calipers out had a similar setup, and would not make the 1300 psi line pressure required by the fronts without the addition of a hydroboost and a 1 1/8" master cylinder and a proportioning valve. With that setup the system made 1500 psi line pressure at the calipers with the pedal about 1/2 way down. I'm sure that car will stop, but as it is still not been road tested I don't know if the rears will still lock up before the fronts, even with a propvalve....

IIRC the Lincoln Versaille used a smaller rear piston caliper than the Mark IV, but those too were a problem when used with small capacity front calipers. I know a couple of road racer guys who said they would have the Versaille calipers resleeved and run a pinto front piston in them to get the bias right when they ran with the early 4 piston mustang calipers...but it proved to be too much hassle.

You still need to tell us if the pedal is hard, with no stopping power, or if it goes to the floor without being able to stop the car...from your pedal measurements it appears that you have a 3.3:1 pedal ratio, which, if the pedal is 5 or so inches from the floor, would give you about 1.5 " of pushrod travel, which is more than enough to utilize the entire stroke of the master cylinder and deliver plenty of volume.......but the 7" booster gives very little assist, even if the vacuum is 20"...I have plumbed brake boosters into the base plate of carbs mounted on blowers, and gotten great vacuum....A high hard pedal tells us that you have enough volume, but not enough assist, while a low easy pedal can mean a number of things.

I have found that plumbing a high pressure gauge into the bleeder port on a front caliper is an invaluable diagnostic tool on mismatched brake systems. The pressure requirements at the front are the greatest, and if you can't get 1300 psi at the fronts, either because you run out of volume, or assist, the car isn't going to stop well.

Another thing you might consider is that the pads are clogged with rust from cleaning off those rotors...

later, mikey

03-24-2009 08:24 AM

302 Z28

I say give them a try, but as Mikey alluded to you might have a problem. I would try and find out what size MC the Lincoln had originally and compare that to the Vette MC. You probably should also employ an adjustable valve to meter the rear brakes.

Vince

03-23-2009 10:16 PM

KULTULZ

Quote:

Originally Posted by whynot

Now I will try to describe the brake setup. The rear is a 9" lincoln lock rear with new calipers pads and etc. The calipers are the dual pistion type that are about 2" in dia. All new brake lines and hoses.

I am not familiar with two piston rear disc. A photo will help.

How to post is explained @ Attach Files

03-23-2009 09:04 PM

whynot

First guys just want to say thanks for the replys. Now I will try to describe the brake setup. The rear is a 9" lincoln lock rear with new calipers pads and etc. The calipers are the dual pistion type that are about 2" in dia. All new brake lines and hoses. The front axle is a new 1930 a model dropped axle with new wilwood calipers,rotors and etc. It has new brake 6" brake booster that are installed in most street rods. The master cylinder is a new 11/8" bore GM dual cast iron type {not plastic. } same as the installed on vetts. The setup is mounted on the firewall. The brake pedal arm is a street rod aftermarket type. Its a hanging type that bolts up on the inside of the firewall,to the brake booster. From the pivit point it 3" down to the brake mc push rod arm. The total length of the brake pedal arm from the pivit point is 10" and the pedal pad sits like 5" off the floodboard/firewall. The car was scale at 1,726 lb with about 10 gallons of gas. The brake booster gets its vacuum from the rear bottom of the carb,like most. Its a 383 sbc, 8-71 blower with 2 780 carbs. I can post pictures if it will help, but not sure how to post in this fourm.

03-22-2009 03:48 AM

KULTULZ

Yes, there is a method to establish correct adjustment in the rear disc.

But first, describe the complete braking system. Where is the MC located? Booster?

03-22-2009 02:02 AM

powerrodsmike

Are these the big old style Lincoln calipers that come on a 9" rear end? Like the 78 or 79 and earlier? ( you did say markIV)..Those have some big pistons, and the last thing you want to do is go smaller on your master cylinder, typically those need a big mc and a booster. I know the guys who used to swear by the lincoln versaille rear brakes on the mustangs, but gave up on them as they could never get them to work just right, as if they got them to work, there was too much rear brake bias.

Is the pedal hard? Or does it go to the floor when you try to stop?

Later,
Mikey

03-22-2009 12:49 AM

whynot

Lincoln mark 4 disc brake rear

Does anyone the correct way to adjust mark 4 rear disc brakes with new calipers and pads. I have the special to to adjust the pistions in, but are they spose to be adjusted all the way in with new calipers,pads and rotors. I also installed a New dual mastercylinder with a one and one eight inch piston. But since was told, I should use a mastercylinder with a small pistion. That smaller will produce more line pressure. I maybe wrong, but I always thought bigger was better. This is a 1,700 lb street rod. with front and rear disc brakes. And everything new, pads calipers,lines,
booster, etc. The front are non-adjust wilwood brakes rear mark 4 disc. This thing should stop on a dime,light as it is.
but it does not. At best its good for a 30 mph slow stop. Will not lockup the wheels. Should I change to a smaller dual master cylinder.